#!/bin/sh
# Copyright (C) 2002-2005 Flavio Stanchina
# Copyright (C) 2005-2006 Aric Cyr
# Copyright (C) 2007 Mario Limonciello
# Copyright (C) 2009 Alberto Milone

set -e

MODDIR="@MODDIR@"

_get_kernel_dir() {
    KVER=$1
    DIR="$MODDIR/$KVER/build"
    echo "$DIR"
}

_check_kernel_dir() {
    DIR=$(_get_kernel_dir "$1")
    test -e "$DIR/include"
    return $?
}

# Check the existence of a kernel named as $1
_is_kernel_name_correct() {
    if [ -e "$MODDIR/$1" ]; then
        echo yes
    else
        echo no
    fi
}


# Get the most recent kernel on Debian based systems. This keeps
# into account both the version and the ABI. If the current kernel
# is the most recent kernel then the function will print a null string.
_get_newest_kernel_debian() {
    NEWEST_KERNEL=
    NEWEST_VERSION=
    NEWEST_ABI=

    for kernel in /boot/config-*; do
        [ -f "$kernel" ] || continue
        KERNEL=${kernel#*-}
        KERNEL_VERSION=${KERNEL%%-*}
        ABI=${KERNEL#*-}
        ABI=${ABI%%-*}

        if [ -z "$NEWEST_KERNEL" ]; then
            # The 1st time get a version which is bigger than $1
            COMPARE_TO=$1
        else
            # Get the biggest version
            COMPARE_TO="$NEWEST_VERSION-$NEWEST_ABI"
        fi

        # if $kernel is greater than $COMPARE_TO
        if [ "$(dpkg --compare-versions "$KERNEL_VERSION-$ABI" ge "$COMPARE_TO" && echo "yes" || \
              echo "no")" = "yes" ]; then
            NEWEST_KERNEL=$KERNEL
            NEWEST_VERSION=$KERNEL_VERSION
            NEWEST_ABI=$ABI
        fi
    done

    echo "$NEWEST_KERNEL"
}

# Get the most recent kernel in Rhel based systems.
_get_newest_kernel_rhel() {
    rpm -q --qf="%{VERSION}-%{RELEASE}.%{ARCH}\n" --whatprovides kernel | tail -n 1
}

# Get the newest kernel on Debian and Rhel based systems.
get_newest_kernel() {
    NEWEST_KERNEL=
    # Try Debian first as rpm can be installed in Debian based distros
    if [ -e /usr/bin/dpkg ]; then
        # If DEB based
        CURRENT_VERSION=${CURRENT_KERNEL%%-*}
        CURRENT_ABI=${CURRENT_KERNEL#*-}
        # shellcheck disable=SC2034
        # not used now, might use it later
        CURRENT_FLAVOUR=${CURRENT_ABI#*-}
        CURRENT_ABI=${CURRENT_ABI%%-*}
        NEWEST_KERNEL=$(_get_newest_kernel_debian "$CURRENT_VERSION-$CURRENT_ABI")

    elif command -v rpm >/dev/null 2>&1; then
        # If RPM based
        NEWEST_KERNEL=$(_get_newest_kernel_rhel)
    fi

    # Make sure that kernel name that we extracted corresponds to an installed
    # kernel
    if [ -n "$NEWEST_KERNEL" ] && [ "$(_is_kernel_name_correct "$NEWEST_KERNEL")" = "no" ]; then
        NEWEST_KERNEL=
    fi

    echo "$NEWEST_KERNEL"
}

NAME=$1
VERSION=$2
TARBALL_ROOT=$3
ARCH=$4
UPGRADE=$5

if [ -z "$NAME" ] || [ -z "$VERSION" ]; then
    echo "Need NAME, and VERSION defined"
    echo "ARCH is optional"
    exit 1
fi

if [ -f /etc/dkms/no-autoinstall ]; then
    echo "autoinstall for dkms modules has been disabled."
    exit 0
fi

# read framework configuration options
for fwcf in /etc/dkms/framework.conf /etc/dkms/framework.conf.d/*.conf ; do
    if [ -f "$fwcf" ] && [ -r "$fwcf" ]; then
        # shellcheck disable=SC1090
        . "$fwcf"
    fi
done

# shellcheck disable=SC2012
# suggests to use find here instead, but that is not equivalent
KERNELS=$(ls -dv "$MODDIR"/*/build 2>/dev/null | sed 's|'"$MODDIR"'/\(.*\)/build|\1|' || true)
CURRENT_KERNEL=$(uname -r)

#We never want to keep an older version side by side to prevent conflicts
if [ -e "/var/lib/dkms/$NAME/$VERSION" ]; then
    echo "Removing old $NAME/$VERSION DKMS files..."
    dkms remove -m "$NAME" -v "$VERSION" --all
fi

#Load new files, by source package and by tarball
if [ -f "$TARBALL_ROOT/$NAME-$VERSION.dkms.tar.gz" ]; then
    if ! dkms ldtarball --archive "$TARBALL_ROOT/$NAME-$VERSION.dkms.tar.gz"; then
        echo ""
        echo ""
        echo "Unable to load DKMS tarball $TARBALL_ROOT/$NAME-$VERSION.dkms.tar.gz."
        echo "Common causes include: "
        echo " - You must be using DKMS 2.1.0.0 or later to support binaries only"
        echo "   distribution specific archives."
        echo " - Corrupt distribution specific archive"
        echo ""
        echo ""
        exit 2
    fi
elif [ -d "/usr/src/$NAME-$VERSION" ]; then
    echo "Loading new $NAME/$VERSION DKMS files..."
    dkms add -m "$NAME" -v "$VERSION" > /dev/null
fi

dkms_conf="/var/lib/dkms/$NAME/$VERSION/source/dkms.conf"
autoinstall=$(bash -c 'AUTOINSTALL=; . "'"$dkms_conf"'" >/dev/null 2>&1; echo $AUTOINSTALL')
if [ -z "$autoinstall" ]; then
    echo "Not building the $NAME module which does not have AUTOINSTALL enabled."
    exit 0
fi

dkms_conf="/var/lib/dkms/$NAME/$VERSION/source/dkms.conf"
autoinstall=$(bash -c 'AUTOINSTALL=; . "'"$dkms_conf"'" >/dev/null 2>&1; echo $AUTOINSTALL')
if [ -z "$autoinstall" ]; then
    echo "Not building the $NAME module which does not have AUTOINSTALL enabled."
    exit 0
fi

# On 1st installation, let us look for a directory
# in $MODDIR which matches $(uname -r). If none
# is found it is possible that buildd is being used
# and that uname -r is giving us the name of the
# kernel used by the buildd machine.
#
# If this is the case we try to build the kernel
# module for each kernel which has a directory in
# $MODDIR. Furthermore we will have to tell
# DKMS which architecture it should build the module
# for (e.g. if the buildd machine is using a
# 2.6.24-23-xen 64bit kernel).
#
# NOTE: if the headers are not installed then the
#       module won't be built, as usual

# Here we look for the most recent kernel so that we can
# build the module for it (in addition to doing it for the
# current kernel).
NEWEST_KERNEL=$(get_newest_kernel)

if [ -z "$autoinstall_all_kernels" ]; then
    # If the current kernel is installed on the system or chroot
    if [ "$(_is_kernel_name_correct "$CURRENT_KERNEL")" = "yes" ]; then
        if [ -n "$NEWEST_KERNEL" ] && [ "${CURRENT_KERNEL}" != "${NEWEST_KERNEL}" ]; then
            KERNELS="$CURRENT_KERNEL $NEWEST_KERNEL"
        else
            KERNELS=$CURRENT_KERNEL
        fi
    # The current kernel is not useful as it's not installed
    else
        echo "It is likely that $CURRENT_KERNEL belongs to a chroot's host"

        # Let's use only the newest kernel if this is not a first installation
        # otherwise build for all kernels
        if [ -n "$NEWEST_KERNEL" ] && [ -n "$UPGRADE" ]; then
            KERNELS="$NEWEST_KERNEL"
        fi
    fi
fi

if [ -z "$KERNELS" ]; then
    echo "WARNING: No kernel headers were found, skipping module build."
    echo "         To get the headers for the running kernel ($CURRENT_KERNEL)"
    echo "         please install the linux-headers-$CURRENT_KERNEL package."
    exit 0
fi

# Take care of displaying newline separated list
echo "Building for $KERNELS" | tr '\n' ',' \
    | sed -e 's/,/, /g; s/, $/\n/; s/, \([^,]\+\)$/ and \1/'

if [ -n "$ARCH" ]; then
    echo "Building for architecture $ARCH"
fi

for KERNEL in $KERNELS; do
    echo ""
    dkms_status=$(dkms status -m "$NAME" -v "$VERSION" -k "$KERNEL" ${ARCH:+-a "$ARCH"})
    if [ "$(echo "$KERNEL" | grep -c "BOOT")" -gt 0 ]; then
        echo "Module build and install for $KERNEL was skipped as "
        echo "it is a BOOT variant"
        continue
    fi

    #if the module isn't yet built, try to build it
    if [ "$(echo "$dkms_status" | grep -c ": built")" -eq 0 ]; then
        if [ ! -L "/var/lib/dkms/$NAME/$VERSION/source" ]; then
            echo "This package appears to be a binaries-only package"
            echo " you will not be able to build against kernel $KERNEL"
            echo " since the package source was not provided"
            continue
        fi
        if _check_kernel_dir "$KERNEL"; then
            echo "Building initial module $NAME/$VERSION for $KERNEL"
            res=0
            dkms build -m "$NAME" -v "$VERSION" -k "$KERNEL" ${ARCH:+-a "$ARCH"} || res=$?
            case "$res" in
            77)
                # skipped due to BUILD_EXCLUSIVE
                continue
                ;;
            0)
                ;;
            *)
                exit $res
                ;;
            esac
            dkms_status=$(dkms status -m "$NAME" -v "$VERSION" -k "$KERNEL" ${ARCH:+-a "$ARCH"})
        else
            echo "Module build for kernel $KERNEL was skipped since the"
            echo "kernel headers for this kernel do not seem to be installed."
        fi
    fi

    #if the module is built (either pre-built or just now), install it
    if [ "$(echo "$dkms_status" | grep -c ": built")" -eq 1 ] &&
       [ "$(echo "$dkms_status" | grep -c ": installed")" -eq 0 ]; then
        dkms install -m "$NAME" -v "$VERSION" -k "$KERNEL" ${ARCH:+-a "$ARCH"}
    fi
done

# vim: et:ts=4:sw=4
